Grouped Licenses Network Analysis
Based on Stoll et al. 2016 license categories
| License Type | Target Species | Stoll 2016 Grouping |
|---|---|---|
| Aquaculture license | Aquaculture | Aquaculture |
| Commercial fishing crew | Finfish | Commercial Fishing |
| Commercial fishing single | Finfish | Commercial Fishing |
| Commercial pelagic and anadromous crew | Pelagic/Anadromous | Pelagic & Anadromous |
| Commercial pelagic and anadromous single | Pelagic/Anadromous | Pelagic & Anadromous |
| Commercial shellfish | Shellfish | Shellfish |
| Commercial shrimp crew | Shrimp | Northern Shrimp |
| Commercial shellfish + 70 | Shellfish | Shellfish |
| Commercial shrimp single | Shrimp | Northern Shrimp |
| Commercial shellfish under 18 | Shellfish | Shellfish |
| Elver dip net | Elver | Elver |
| Elver dip net crew | Elver | Elver |
| Elver 1 fyke net | Elver | Elver |
| Elver 1 fyke net crew | Elver | Elver |
| Elver 2 fyke net | Elver | Elver |
| Elver 2 fyke net with crew | Elver | Elver |
| Elver dip net 1 fyke net | Elver | Elver |
| Elver dip net 1 fyke net crew | Elver | Elver |
| Eel pot | Eel | Eel |
| Green crab | Green crab | Green crab |
| Lobster crab apprentice | Lobster | Lobster Apprentice & Student |
| Lobster crab apprentice + 70 | Lobster | Lobster Apprentice & Student |
| Lobster crab apprentace under 18 | Lobster | Lobster Apprentice & Student |
| Lobster crab class i | Lobster | Lobster Class I |
| Lobster crab class ii | Lobster | Lobster Class II |
| Lobster crab class ii + 70 | Lobster | Lobster Class II |
| Lobster crab class iii | Lobster | Lobster Class III |
| Lobster crab class iii + 70 | Lobster | Lobster Class III |
| Lobster crab + 70 | Lobster | Lobster Crab |
| Lobster crab student | Lobster | Lobster Apprentice & Student |
| Lobster crab under 18 | Lobster | Lobster Apprentice & Student |
| Mussel dragger | Mussel | Mussel |
| Menhaden commercial | Menhaden | Menhaden |
| Menhaden non commercial | Menhaden | Menhaden |
| Mussel hand | Mussel | Mussel |
| Marine worm digging | Marine worm | Marine worm |
| Quahog (mahogany) | Quahog clam | Mahogany Clam |
| Sea cucumber drag | Sea cucumber | Sea Cucumber |
| Scallop dragger | Scallop | Scallop (Dragger) |
| Scallop diver | Scallop | Scallop (Hand) |
| Scallop with tender | Scallop | Scallop (Tender) |
| Spat | Spat | Spat |
| Sea urchin dragger | Sea urchin | Sea Urchin (Dragger) |
| Sea urchin diver | Sea urchin | Sea Urchin (Hand) |
| Sea urchin raking | Sea urchin | Sea Urchin (Hand) |
| Surf clam boat | Surf clam | Surf Clam |
| Sea urchin with tender | Sea urchin | Sea Urchin (Tender) |
| Seaweed | Seaweed | Seaweed |
| Seaweed supplemental | Seaweed | Seaweed |
Portfolio by License Subdivisions
Using Theresa Burnham’s code for building the individual license portfolio, license types were grouped license divisions as described in Stoll et al. 2016. A binary matrix was created, whereas 1 denotes an individual license holding for a corresponding year and 0 denotes no license held. With this co-occurrence matrix, we can quantify which license types were held together over the past 30 years and how those holdings have changed.
Annual Species Metrics
Degree centrality
“The degree of a node is the number of other nodes that single node is connected to.
Important nodes tend to have more connections to other nodes. Highly connected nodes are interpreted to have high degree centrality.”
Betweeness
“[Betweenness] ranks the nodes based on the flow of connections through the network. Importance is demonstrated through high frequency of connection with multiple other nodes. Nodes with high levels of betweenness tend to serve as a bridge for multiple sets of other important nodes.” Source
Annual Network Plots
Edge Density and Modularity
